1. Field of the Invention
This invention relates to a hinge, and in particular a damped hinge.
2. Description of the Prior Art
Spring-biased hinges are commonly used in many consumer products for opening lids or doors automatically on release of a latch. Two examples of such products are radiotelephones and cameras. A spring-biased hinge may be used on a radiotelephone to open a flip, where the flip is used to cover the main radiotelephone housing. A spring-biased hinge may be used on a camera to open a lens cover, where the lens cover is used to protect the lens of the camera.
Typically the hinge is arranged to couple one element of a device to the main housing of the device such that when the element is closed a latch maintains the element in the closed position with the spring bias of the hinge acting against the latch. When the latch is released the spring bias of the hinge rotates the element way from the main housing.
To prevent damage to a device, as a result of a spring-biased hinge rotating open a lid or a door, silicon oil and grease have been incorporated into springbiased hinges to control the rate of rotation of the spring-biased hinge when opening (i.e. dampen the rate of rotation). The oil/grease acts as an energy absorber allowing the hinge to open, under the spring bias, in a relatively slow and controlled manner.
However, the ability of oil/grease to act as an energy absorber can vary with variations in temperature. Further, the manufacture of a damped hinge using oil/grease as an energy absorber can be difficult and complex, which can increase manufacturing costs and may effect the reliability of the hinge. Oil/grease can also leak from the hinge, which may not only create a mess but may also affect the dampening performance of the hinge.
It would be desirable to improve this situation.
In accordance with a first aspect of the present invention there is provided a damped hinge comprising a first part mounted to a second part to allow relative rotation between the first and second part; biasing means for providing rotational movement between the first and second part; wherein upon rotational movement between the first and second part the first and second parts are arranged to co-operate to dampen the rotational movement.
This has the advantage of minimizing the number of manufacturing processes required for manufacturing the damped hinge while allowing the dampening performance of the hinge to be relatively temperature independent.
Preferably the first and second parts are sized such that upon rotational movement between the first and second part the first part moves against the second part to dampen the rotational movement.
Most preferably the first part includes a resilient element such that upon rotational movement between the first and second part, the resilient element moves against the second part to dampen the rotational movement.
Preferably the first part is eccentrically mounted within the second part with respect to the axis of rotation.
This has the advantage of varying the energy absorption (i.e. dampening) non-linearly, thereby allowing the rate of rotation of the hinge to vary between its open and closed position. This allows the hinge to initially rotate open relatively quickly, for example, with the rotation rate decreasing as the hinge approaches its open position.
Preferably the second part has a cylindrical section for housing the first part, the cylindrical section being eccentrically positioned with respect to the axis of rotation.
Preferably the damped hinge further comprises a latch for maintaining the first part in a first position relative to the second part.
Most preferably, the damped hinge further comprises means responsive to a longitudinal movement with respect to the first or second part of the hinge for releasing the latch, wherein the biasing means is arranged to rotate the first part relative to the second part upon release of the latch.
This has the advantage of allowing the hinge to be opened by depressing the hinge along the hinge""s longitudinal axis.
According to a second aspect of the present invention, there is provided an apparatus having a first element, a second element and a hinge, the hinge comprising a first part for mounting to the first element; a second part for mounting to the second element; the first part being mounted to the second part to allow relative rotation between the first and second part; biasing means for providing rotational movement between the first and second part; wherein upon rotational movement between the first and second part the first and second parts are arranged to co-operate to dampen the rotational movement.
In accordance with a third aspect of the present invention there is provided a radiotelephone having a first element, a second element and a hinge, the hinge comprising a first part for mounting to the first element; a second part for mounting to the second element; the first part being mounted to the second part to allow relative rotation between the first and second part; biasing means for providing rotational movement between the first and second part; wherein upon rotational movement between the first and second part the first and second parts are arranged to co-operate to dampen the rotational movement.